Between 1996 and 1998, 1064 cases of giardiosis were reported in Norway, with less than 25% attributed to infection acquired within the countryBetween 1999 and 2002, 1547 cases of giardiosis were reported (mean of 386 cases per year; 8.5 cases per 100,000 population). The rise in the rate of infection is attributed to increased immigration and foreign travel (Folkehelseinstituttet, 2002).